Web APIs Issue Tracker wrote:
http://groups.google.com/group/mozilla.dev.tech.xml/browse_thread/thread/74257e17b66e68e8/8e0b8aded9bac4a0 points out that only Mozilla has a funny implementation like that where all other implementations just reset the object.
Please see the remainder of that thread, and in particular see http://groups.google.com/group/mozilla.dev.tech.xml/tree/browse_frm/thread/74257e17b66e68e8/8e0b8aded9bac4a0?rnum=1&_done=%2Fgroup%2Fmozilla.dev.tech.xml%2Fbrowse_frm%2Fthread%2F74257e17b66e68e8%2F8e0b8aded9bac4a0%3Ftvc%3D1%26#doc_8bfcb7bc6d4f97a4 and the bug referenced therein, which describes IE's behavior. IE does set the readyState to 4 in some cases, but not in others, apparently.
-Boris
